If you are having trouble with signing in Outlook 2010 (the desktop version), please try the following troubleshooting steps:
Make sure your login username is "UOFI\your_netid"
Check your account information by clicking the "File" tab (the first one from left), by default the "Info" category is highlighted in the left navigation pane (if not, click to select it), on the right, make sure your email address appears under the "Account Information" (see example below).
If you do NOT see "email@example.com" listed under "Account Information", click "Add Account" button (the green plus sign).
The "Add New Account" dialog box pops up, type in your name, your email (should be "firstname.lastname@example.org"), and password (twice, once in each box), then click "Next" button in the lower right corner.
Outlook will automatically configure the account for you (this may take a minute or so), wait till you see three green check marks and a message below them reads "Your e-mail account is successfully configured", click the "Finish" button in the lower right corner.
Under "File" tabe and "Info" category, check to see whether "email@example.com" is listed under "Account Information", then click "Account Setting" button and select "Account Setting..." from the drop down list.
The "Account Settings" dialog box pops up, check to see whether "firstname.lastname@example.org" is the only account listed under "Email" tab in the "Name" column, if yes, click "Close" in the lower right corner, and then follow the instruction on the Change Outlook Account Setting after Upgraded to Exchange 2010 page to set up your account settings.
If you have multiple accounts listed under "Email" tab in the "Name" column, make sure "email@example.com" is the default account (the default account has a check mark button in front of it (see example below), if not, click firstname.lastname@example.org to highlight it, and then click the "Set as Default" button to set it as default.
To remove the unwanted account, click the account to highlight it (in this example, I'm using an gmail account), and then click the "Remove" button to delete it. Then click "Close" button in the lower right corner. Your Outlook is set up now.